Dio started out in rockabilly bands, but moved on to the wildly popular heavy-metal sound of the 1970s. He sang for the band Rainbow, which was founded by former Deep Purple guitarist Ritchie Blackmore, and he replaced Ozzy Osbourne after the notoriously unruly vocalist was fired by Black Sabbath. With Dio as vocalist, Black Sabbath released an album, Heaven and Hell, that’s credited with reviving the band’s flagging popularity.

After another album with Black Sabbath, the vocalist formed his own band, Dio. The band’s album Holy Diver is considered a heavy-metal classic. Throughout his career, Dio was known for his “devil’s gesture”-raising his hand with the second and fifth fingers up, and the rest down. Although many critics (and fans) was indicative of devil worship and occultism, Dio himself said his Italian grandmother taught him the gesture as a way to ward off (and impose) the “evil eye”. (New York Times)